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Finding the Fourth Proportional to 711.80, 1,066.48 and 387.40

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Solution

The fourth proportional to 711.80, 1,066.48 and 387.40 is: 580.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    711.80 : 1,066.48 = 387.40 : x
  2. Step 2: Convert to fraction form
    711.80/1,066.48 = 387.40/x
  3. Step 3: Cross multiply
    711.80x = 1,066.48 × 387.40
  4. Step 4: Simplify right side
    711.80x = 413,154.35
  5. Step 5: Solve for x
    x = 413,154.35/711.80
  6. Step 6: Final answer
    x = 580.44

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.